1. Field of the Invention
This invention relates to iron compounds for use in pharmaceutical compositions for the treatment of iron deficiency anaemia.
2. Description of the Background
An adequate supply of iron to the body is an essential requirement for tissue growth in both man and animals. Although there is normally an ample amount of iron in the diet, the level of absorption of iron from food is generally low so that the supply of iron to the body can easily become critical under a variety of conditions. Iron deficiency anaemia is commonly encountered in pregnancy and may also present a problem in the newly born, particularly in certain animal species such as the pig. Moreover, in certain pathological conditions there is a maldistribution of body iron leading to a state of chronic anaemia. This is seen in chronic diseases such as rheumatoid arthritis, certain haemolytic diseases and cancer.
Although a wide range of iron compounds is already marketed for the treatment of iron deficiency anaemia, the level of iron uptake by the body from these compounds is often quite low, necessitating the administration of relatively high dosage levels of the compound. The administration of high dose, poorly absorbed, iron complexes may cause siderosis of the gut wall and a variety of side effects such as nausea, vomiting, constipation and heavy malodorous stools.
In UK patent application No. 8230148, now published as Application No. GB 2,117,766A (corresponding to U.S. application Ser. No. 478,494), now U.S. Pat. No. 4,550,101, we describe a group of iron complexes which we have identified as being of particular value for use at relatively low dosage levels in the treatment of iron deficiency anaemia. These compounds consist of iron complexes of 3-hydroxypyrid-2-ones and 3-hydroxypyrid-4-ones in which the nitrogen atom and optionally one or more of the carbon atoms of the ring are substituted by an aliphatic hydrocarbon group, particularly of 1 to 6 carbon atoms. We have now found that the iron complexes of 3-hydroxypyrid-2-ones and 3-hydroxypyrid-4-ones containing other ring substituents are also of particular value in the treatment of such conditions.